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Hello all,
I am thoroughly confounded with my Carvin X-60b head. It has been modified to run EL-34s instead of the usual 6L6. It was also modified to have external bias measurement points. These can be seen in the pics here.

I also included some high res pics of the PCB. Click "full size" in the upper left corner to blow the image up. The problem I am having is I can't find the bias pot! I am told that some of these amps were fixed bias. However, I would think that since it has bias measurement points, it ought to have a bias pot on it as well, right? Does anyone have any thoughts on this? Also, on the back is written "Leave Standby Off when measuring bias". This seems odd to me that you would leave the amp in standby when measuring bias. I always thought you were supposed to take the amp out of standby to measure plate voltage? I have some Mullard reissues that I'd like to stick in, but I'm hesitant until I know the bias is right. Also, does anyone know what the proper voltage range is that I should be looking for?

Any thoughts on this would be greatly appreciated.

Thanks,
Jon